This invention relates generally to surgical apparatus and the manufacture thereof and, more particularly, to a conduit for transporting blood between blood vessels during surgical procedures without significant blood loss and without the need for potentially damaging and difficult to use clamps or ties for attaching the conduit to the vessels.
Various types of conduits for transporting blood between blood vessels are known. For example, U.S. Pat. No. 3,435,824 describes a surgical apparatus which may be used in by-passing an arterial vessel so that the flow of blood can continue while a diseased section of the vessel is corrected. The apparatus includes a tube with a continuous axially disposed bore and inflatable means encircling the end portions of the tube for maintaining the tube in position within the circulatory system.
An indwelling double balloon shunt for carotid endarterectomy is described in a technical note authored by Furui and Hasuo, which appeared in the Journal of Neurosurgery, 60: 861-863, 1984. The shunt described comprises a soft silicone tube equipped with silicone balloons at both ends which are inflated to hold the tube in place during the endarterectomy procedure while preventing bleeding from the gap between the tube and the inner surface of the carotid arteries. Other double balloon shunts are commercially available using a rigid vinyl tube instead of the silicone tube used by Furui and Hasuo.
Both prior rigid and resilient blood flow conduits bearing inflatable balloons at the conduit ends for occluding blood flow between a blood vessel and the outer surface of the tube have significant drawbacks. For example, when the tubes are made of a rigid material such as vinyl, insertion into the blood vessels can cause displacement of arterial plaque and damage to the vessel wall. Furthermore, such rigid tubes may traumatize the blood cells which pass through them. On the other hand, when the more resilient silicone tubes are used, it is sometimes difficult to guide the highly flexible tube ends into the vessel. Also, once the tubes are inserted and the balloons are inflated, the inadvertent application of excess pressure in the balloons may collapse the tube thereby occluding the lumen and blocking or impeding blood flow.
Other potential problems with present blood flow conduits include the difficulty of sensing blood flow in the conduit and the danger of puncturing an inflated balloon with a sharp instrument while performing, for example, an endarterectomy procedure. With particular reference to the endarterectomy procedure, prior art devices generally follow a "one size fits all" philosophy, failing to provide a longer conduit branch for the common carotid which is longer than the internal carotid and typically contains plaque to a greater depth than found in the internal carotid.
Finally, the methods used in manufacturing prior art devices of the present type are generally complex and result in an unduly expensive product.